Oh I wish I was the one providing this information, but instead I found such an thorough and well thought-through answer on StackExchange that I thought I had to point it out. So, t0 the question: What is AVR Arduino interrupt latency? And how can it be shortened The answers can be found in this StackExchange …
This story continues at What is Arduino interrupt latency? And how to shorten it
Or just read more coverage at Electronics Weekly